/Engine/Plugins/Experimental/PlanarCutPlugin/Source/PlanarCut/Public/PlanarCut.h
Split the geometry at the given transforms into their connected components
index of first new geometry in the Output GeometryCollection, or -1 if no geometry was added
int32 SplitIslands ( [FGeometryCollection](API\Runtime\Chaos\GeometryCollection\FGeometryCollection) & Collection, const [TArrayView](API\Runtime\Core\Containers\TArrayView)< const int32 > & TransformIndices, double CollisionSampleSpacing, [FProgressCancel](API\Runtime\GeometryCore\Util\FProgressCancel) * Progress )